#include<stdio.h>

int judgeTriangle(int,int,int) ; 

int main()
{
    int        a, b, c ;    

    scanf("%d%d%d",&a,&b,&c);

    switch(judgeTriangle(a,b,c))
    {
        case    -1    :    printf("It is not a triangle.\n") ;    break ;
        case    0    :    printf("It is a scalenous triangle.\n") ;    break ;
        case    1    :    printf("It is a right-angled triangle.\n") ;    break ;
        case    2    :    printf("It is an isosceles triangle.\n") ;    break ;
        case    3    :    printf("It is a equilateral triangle.\n") ;    break ;
    }

    return 0;
}

int judgeTriangle(int a,int b,int c)
{
    int d;
    if((a+b-c)<0||(a+c-b)<0||(c+b-a)<0) d=-1;
    else
    {
        d=0;
        if((a*a+b*b)==c*c||(c*c+b*b)==a*a||(a*a+c*c)==b*b) d=1;
        if(a==b||b==c||a==c) d=2;
     
        if(a==b&&b==c) d=3;

    }
    return d;
}